03 GMC Yukon. Need to change the Oil sending unit.. where is it

2008, I would start with replacing the oil pressure sending unit. Or maybe adding oil.

Sorry not familiar with gasket replacements

You hook up a mechanical oil pressure gauge at the oil pressure sending unit oil port and test the pressure, it should be about 25 PSI hot idle and about 50PSI at 2-3,000 RPM.

Your oil pressure sending unit may be damaged or wearing out. You need to get the pressure affirmed so that you don't destroy your engine, but if you get a new sending unit and the pressure returns to normal you should be good to go. Thats the cheapeast way to go is to get a new sending unit and change it out or you can get the pressure verified by a mechanic which will charge for labor and then you may have to get a new unit anyway so the cost of just swapping the unit is less than a mechanic and the results will yield the same information. If the new unit does not settle the issue then you have some delivery problem either with your pump or a blockage of some sort.

THE OIL SENDING UNIT IS USUALLY LOCATED ON OIL PAN OR JUST ABOVE. HAS SINGLE WIRE OUT BECAUSE IT GROUNDS OFF MOTOR

on the top rear of the block.

You probably just have a bad oil sending unit.Check the oil level first to make sure it is not over full.The sending unit is in the rear of the motor.Not easy to get to but if you look back there with a light you should be able to see it.Hope this helps.Good luck.

my 2004 yukon engine oil sensor is at its highest, what is the problem

Probably just the oil sending unit internally defective.Just have them install a pressure tester and make sure the pressure is good.I`m sure this will be the sending unit.Hope this helps.Good luck.

you will need to put a pressure gauge right on the engine to see whats real. Do an oil service with filter. This could help, If the pressure is stll low you could put a oil pump in and hope for the best. As long as you have pressure you should be ok. 20psi at idle can be a sign of old oil so cross your fingers.